This invention relates to a magnetic recording medium excellent in wear resistance of a magnetic layer, durability, and surface smoothness, and improved in suppression of wear at a magnetic head.
Heretofore, magnetic recording media for audio, video and computer have employed a process for incorporating as a reinforcing material a non-magnetic powder having an average primary particle size of about 0.5 .mu.m or more such as Al.sub.2 O.sub.3, Cr.sub.2 O.sub.3, SiC, etc. into a magnetic layer. The incorporation of the reinforcing material improves wear resistance and durability of the magnetic recording media, but on the other hand brings about various disadvantages in that there is a tendency to increase wear and injury of magnetic heads, and surface smoothness of the magentic layer is lowered and electromagnetic transforming properties are deteriorated. Particularly, since high density of magnetic recording is intended recently by thinning the magnetic layer using a metallic magnetic powder or fine magnetic powder, the addition of the non-magnetic powder as reinforcing material promotes disadvantages such as an increase of wear and injury of magnetic head, lowering in smoothness of the magnetic layer, and lowering in electro-magnetic transforming properties.
In order to improve such disadvantages, it is proposed to add a non-magnetic powder having a very fine particle size (generally 0.4 .mu.m or less) as a reinforcing material, but such a non-magnetic powder having a very fine particle size hardly contributes to improve the wear resistance and durability of magnetic layer, and thus not satisfactory.